Field of Endeavor
The present invention relates to relates to inertial confinement fusion, inertial fusion energy, and more particularly to a hybrid indirect-drive/direct-drive target for inertial confinement fusion.
State of Technology
In inertial confinement fusion (ICF), a driver—i.e., a laser, heavy-ion beam or a pulse power system—delivers an intense energy pulse to a target containing around a milligram of deuterium-tritium (DT) fusion fuel in the form of a hollow shell. The fuel shell is rapidly compressed to high densities and temperatures sufficient for thermonuclear fusion to commence. The goal of present ICF research is to obtain ignition and fusion energy gain from a DT target. The gain of an ICF target is defined as the ratio of the fusion energy produced to the driver energy incident on the target and is a key parameter in determining economic viability of future inertial fusion energy power plants. The two primary methods of driving ICF targets are “indirect-drive” and “direct-drive.”
The National Ignition Facility (NIF) is presently seeking to demonstrate laser-driven ICF ignition and fusion energy gain in the laboratory for the first time by means of indirect-drive. In the latter, the laser energy is first converted to x-rays in a hohlraum surrounding the fuel capsule and the x-rays then perform the ablatively-driven compression of the capsule. Direct-drive is an alternative method of imploding ICF targets where the laser beams impinge directly on the capsule surface and directly cause ablation compression. In both cases, ignition is initiated by the PdV work of the high-velocity converging shell stagnating on a central hotspot. Applicant can define this ignition method as “fast compression ignition”.